StarWatch: Moravian College Astronomy

SEPTEMBER 2021

SEPTEMBER STAR MAP | MOON PHASE CALENDAR | STARWATCH INDEX | NIGHT SKY NOTEBOOK

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lunar phases

1307 September 5, 2021: Follow the Waxing Moon: Each month the moon presents its different phases over a 29.5-day interval passing many celestial objects of interest along the way. Although there is a monthly repetition to this process, Luna presents an enjoyable way of learning the sky along its orbital pathway. Let’s take a look at points of interest along the moon’s journey across the sky during the next eleven days.
September 6: Luna is new late in the day, invisible to us because it is positioned between the Earth and the sun, rising and setting with Sol. Tomorrow, the one percent sunlit moon stands above the planet Mars, too close to the sun for easy observation.
September 8: A razor-thin crescent moon is positioned five degrees above and slightly to the right of Mercury, 30 minutes after sundown in the west. Binoculars are recommended for Mercury. An unobscured western horizon is mandated.
September 9: Venus, the 11 percent lit crescent moon, and the bright star Spica of Virgo the Virgin all lie within the same binocular field of view, 45 minutes after sunset, low in the SW. Binoculars (for Spica) and a southwestern horizon free of obscurations are needed.
September 12: That bright luminary below and to the left of the crescent moon is Antares, the alpha star of Scorpius the Scorpion, a red supergiant near the end of its life. Their separation is 3-1/2 degrees, another nice starscape when viewed through binoculars.
September 13: The moon is at first quarter tonight, half on, half off with its light to the right. View Luna by 10 p.m.
September 14: The moon is now a waning gibbous, more than half lit. This evening finds it in the star pattern of Sagittarius, three degrees below the bright globular cluster M22, an aggregate of about 70,000 stars, 10,000 light years distant, in the general direction of the center of our Milky Way Galaxy. Binoculars will be necessary to spot this ancient globular because of moonlight. M22 will look like a faint, fuzzy, circular smudge of light above the moon. Keep the moon away from the field of view to be able to see the globular cluster more clearly. The best view will be about 90 minutes after sundown. Look south.
September 16: The fat waxing gibbous moon is positioned four degrees below Saturn, easily perceived within the same field of view of most binoculars, but also beautiful to behold with just the unaided eye. The best time to view is around 10 p.m. when the pair will be highest in the southern sky. The moon will only be about 30 degrees above the horizon. That bright “star” to the left is Jupiter.
September 17: At 10 p.m. you’ll find the moon below and to the right of magnificently bright Jupiter. The pair will be separated by just over six degrees, a tight fit for many binoculars, but doable. If you look critically at Jupiter with your binoculars, you might be able to spot the brightest Jovian moon, Ganymede, just to the left of the gas giant. Then look at the moon. You’ll see the dark maria (lunar seas) where huge asteroids struck nearly 3.9 billion years ago, erasing the moon’s past history. The craters formed from these deep impacts oozed darker lava from the moon’s interior for several hundred million years, inundating the impact basins. You’ll also observe the brighter, crater-saturated highlands which did not undergo these large-scale tumultuous events. Look for the splash marks left by smaller asteroids that struck the moon more “recently” in the last billion years or so. When you have had enough of the moon, lower your binoculars to see how the moon’s brilliance has influenced your vision. You’ll probably be blinded for a minute or so. We will continue to follow the moon in its waning cycle in two weeks. Ad Astra!

1308

September 12, 2021: Harvest Moon: What’s in a Name?

As we advance towards the first day of autumn on September 22, the moon is also waxing towards its full phase which will occur on the 20th. Of the 12 or 13 full moons that can occur during the time span of one year, the Harvest Moon is probably the best known. • Before electric lamps, farmers gathering their crops by day, could continue working after sundown because successive bright moon risings at or near the autumnal equinox occurred with the smallest difference in time. • Here is the schedule of moonrises for my hometown from September 18 to the 22nd using a 24-hour clock: S-18, 18:26; S-19, 18:54; Full Moon S-20, 19:20; S-21; 19:43 and S-22, 20:05. That’s an average difference of just under 25 minutes each evening. At the time of moonrise on September 22, the heavens will be at the beginning of nautical twilight with only the brightest stars beginning to become visible. • If you don’t think that you can navigate or continue working by only the light of a full or nearly full moon, think again. Hiking at night in Utah’s Bryce Canyon National Park around the time of full moon was easier done in moonlight. My headlamp, although plenty bright, produced a flat view of the trail with almost no contrast, making it difficult to see obstacles like dust-covered rocks, depressions, and tree roots. The full moon, although less bright than my headlamp, produced plenty of shadow detail making the trail easier to navigate. • The Harvest Moon results from the shallow angle that the moon’s orbit makes to the horizon at this time of the year. On the night of full moon, Luna rises at or very near the time of sundown. For the next several days, the moon’s orbital motion carries it about 13 degrees eastward, but that same motion takes Luna only about five degrees farther below the horizon. The Earth’s rotation then brings the moon above the horizon at nearly the same time for several evenings—25 minutes later for our latitude of 40 degrees north. The effect is even more pronounced in Europe where the moon’s orbital plane is tilted even less to the horizon and differences in successive moonrises can be as little as 10 minutes. • Recently a colleague of mine, Bonnie Brooks, sent me an extensive inventory of Native North American moon names. I thought it might be noteworthy to see how indigenous peoples who lived in locations where seasonal changes occurred labeled their September moons. Here are examples starting with the tribe, its general location, and their September moon’s name. Abenaki—Northeast, Maine (Corn Maker Moon); Algonquin—Northeast to Great Lakes (Middle Between Harvest and Eating Corn Moon); Assiniboine—Northern Plains (Yellow Leaf Moon); Chippewa—Lake Superior and westward (Rice Moon); Arapaho—Great Plains (Drying Grass Moon); Cherokee—East Coast, Carolinas (Nut Moon); Cree—Northern Plains, Canada (Snow Goose Moon); Creek—Southeast, Alabama, Georgia (Little Chestnut Moon); Haida—Alaska (Ice Moon); Hopi—Northwestern Arizona (Moon of Full Harvest); Inuit—Alaska (Harpoon Moon); Kalapuya—Willamette Valley, Oregon (Moon After Harvest); Lakota—Northern Plains (Moon of Brown Leaves); Mohawk—Eastern Woodlands (Time of Much Freshness Moon); Omaha—Central Plains, Nebraska (Moon When the Deer Paw the Earth); Passamaquoddy—Northeast U.S. - St. Croix River Region (Autumn Moon); Shawnee—Midwest, Ohio, Pennsylvania (Papaw* Moon); Sioux—Great Plains, Dakotas, Nebraska (Calves Grow Hair Moon); Tlingit—Pacific Northwest Coast (Big Moon); Wishram—Columbia River, Washington, Oregon (Her Acorns’ Moon); and Zuni—Southwest New Mexico (Corn is Harvested Moon). The September moon for these Native Americans denoted the time of gathering, storing food for winter, or marking the season’s change. How rich were their observations and descriptions! Ad Astra! *Papaw: A small deciduous tree native to the eastern United States and Canada, that produces a large, yellowish-green to brown fruit—Wikipedia.

1309 September 19, 2021: Follow the Waning Moon: Two weeks ago, we followed the moon while it was waxing or growing, tagging along as it passed various objects of interest along its path around the sky. This week, let me take you on a tour of the heavens as the moon wanes, intercepting objects of interest as it diminishes in brightness to a new moon on October 6.
September 19: The moon this evening is near to Neptune, the last planet in our solar system.
September 20: Luna is completely illuminated tonight, a near perfect Harvest Moon, the name of the full moon closest to the autumnal equinox. For a few days before and after this full moon, Luna will rise with the smallest difference in its time of rising. Also this evening, the projection of the Earth’s shadow called the umbra is positioned about five degrees above the full moon. If the moon were to intersect the umbra tonight, a lunar eclipse would occur. No eclipse happens; however, the full moon will rendezvous with Earth’s shadow on November 19 just after 2 a.m. for the start of a deep partial lunar eclipse that will last for nearly four hours.
September 23/24: The waning gibbous moon is equally distant from the planet Uranus on both of these evenings. On the 23rd, Uranus is seven degrees to the left of the moon and on the 24th, Uranus can be found six degrees to the moon’s right. Observe around 11 p.m. Look east to get a general location for this Greek creation god.
September 25: Five degrees above the moon is positioned the Pleiades or Seven Sisters, one of the brightest star clusters in all of the heavens. In a dark sky they usually look like a small hazy patch of light with a half dozen, faint, twinkling luminaries embedded within the nebulosity. Because of the nearness of the moon to the Pleiades, I would recommend using binoculars to see them or observe the Pleiades with averted or side vision to make them pop. Below the moon is the alpha (brightest) star of Taurus the Bull, Aldebaran. Observe around midnight. Look east.
September 26: The moon has now moved to the left of Aldebaran on its 27.3-day journey around the sky. By 5 a.m. the sky orientation places the moon above Aldebaran. Observe after 1 a.m. until dawn. Look east early; in the south, later.
September 28: At 5 a.m. the waning gibbous moon is high above the constellation of Orion the Hunter. Look mid-sky for the easily recognizable belt stars. Right to left, Mintaka, Alnilam, and Alnitak are arranged in a straight line and easily visible in the same binocular field of view. Later in the day, the moon will reach last quarter, half on, half off, with its light to the left.
September 30: The fat, waning crescent moon is below and to the right of Pollux, the brightest star of the Gemini Twins. Above Pollux sits his brother, Castor. Observe around 5:00 a.m. in the southeast.
October 3: A thin, waning “smiley” moon is positioned to the right of the alpha star of Leo the Lion, Regulus. Look east at 5:30 a.m.
October 6: The moon is new and invisible again because it is situated between the sun and the Earth. The lunar cycle begins anew.

1310 September 26, 2021: CHAPEA: It’s Not a Dominican Bean Stew: The world is too complicated a place for an abbreviation not to mean something else in English or in a foreign language. To the Mars enthusiast, CHAPEA is not a Dominican bean stew. It is NASA’s acronym for Crew Health and Performance Exploration Analog, which I believe will be the key to a successful Mars exploration mission. • For decades we have had the capabilities of going to the Red Planet, just not the money nor the will to meet the challenges. One of the great hurtles of any multi-year mission will be the crew’s ability to cooperate with one another and stay mission focused. That is what CHAPEA will be investigating during a year-long mission where a crew of four astronauts will be sequestered in an austere 1700 square foot habitat constructed by a 3D printer. To keep the crew on its toes, the “astronauts” will be monitored by a group of NASA scientists enthusiastically committed to ensuring that things go wrong during the mission. • CHAPEA applicants must be a permanent resident or citizen of the US, between the ages of 30 and 55, in good physical shape with no dietary restrictions, possess a master’s degree and two years of experience in a STEM-related field or engineering or 1000 hours of pilot-in-command time on jet aircraft. Here is the most important part. Finalists will undergo psychological testing and psychiatric screening to determine their suitability for a physically and mentally challenging, long-duration, isolation mission. • As a member of the Mars Society and charged with helping to maintain the astronomical observatories housed at the Mars Desert Research Station near Hanksville, Utah, I have had a little experience working with people in tight quarters. To tell the truth, I don’t think I’d make it to Mars alive. On one occasion I got into a row with a former student and Moravian graduate over my inabilities to scrub a flash drive of its data fast enough so that she could use it to compile video footage of how to operate MDRS’s Musk Observatory. As I write this, I’m embarrassed to admit how trivial, yet intense our exchange became. • There were seven of us living in a two-story, 900 square foot habitat, but we weren’t in simulation. So to decompress, I simply took a half mile walk and sat down on a small, rocky hilltop, and let the winds of a warm summer’s afternoon diffuse my irritations. I could not do that if I were in transit to Mars nor if I were on the planet. It takes over a day to prepare a spacesuit for an extravehicular activity on the International Space Station, something you don’t see in Hollywood blockbusters like The Martian or Gravity where astronauts in only 15-20 seconds are able to “suit up” and begin their EVAs. • The successful CHAPEA candidate would most likely be qualified to go into space on a real Mars mission, although NASA is not equating the two possibilities at this time. • No, not me, please! I feel isolated enough by just wearing a mask. Ad Astra!